百ひゃく年ねん河か清せい

expression

waiting in vain for an unlikely event

A yojijukugo literally meaning 'waiting a hundred years for the Yellow River to clear', used to describe futile waiting for something that will never happen. Equivalent to English idioms like 'when pigs fly'.

• 彼かれが約やく束そくを守まもるのを待まつのは百ひゃく年ねん河か清せいだ。

  Waiting for him to keep his promise is like waiting for pigs to fly.